I have used the TASC CD and found the first three steps to be fairly easy. Step four was tougher and Step 5 was somewhat brutal for me. I plan on doing them again at a slower pace. My opinion is that upon serious study, one could become a fairly competent tactician using this program. Hard Copy books in English can be ordered from Cajun Chess. (except for step 6) I wonder if using the books would be more beneficial.
Step Method

The workbooks are good tactics books. The ones from step 4 and 5 got me from +- 1700 to +- 1900 I think. There are in between books like 4+ and 5+ now as well.
I like the system a lot.

I have it working on Windows XP without any problems, but I can't speak for Vista or Windows 7. The Chesshouse is giving it away for free, you just have to pay for shipping. Here's the link : http://bit.ly/cBD8D.

In reference to the Step Method, I have a question concerning when to use the extra and plus workbooks. I have the manual, workbook (can't find the extra/plus books right now). do you start using the extra/plus books as you are going thru the work book, lesson by lesson or do you use them at the end of the workbook. I see in the back of trainers manual that the plus exercises (8) are listed after all the lessons. but there is no mention of when to do them. I'm assuming that the extra/plus exercises are done immediately following each lesson. can you please clarify this or point me to someone that can?
I have blogged about a Dutch training system called the Step Method. I was wondering if anyone has had any success with this system.